The present invention relates generally to an electromechanical actuator for driving a mechanism between open and closed positions.
Automation of fuel filling has been the subject of interest in the automotive industry. In this regard, automatic fuel filler doors, which automatically open and close to allow access to a vehicle fuel filler, are envisioned. In one design, such a door may include a valve, such as a ball valve, which rotates under the control of an actuator to allow access to the fuel filler port. Importantly, the actuator should reliably rotate the valve from the closed position to the open position to permit fueling the vehicle and then drive the mechanism or valve back to the closed position.
An anti-pinch safety feature may also be required for protecting against a shearing effect created as the valve rotates to close the fuel filler port. For example, absent anti-pinch protection fingers may be injured if inadvertently placed in the port while the door is closing. In addition, system damage may occur, if for example, the door is closed on a gasoline pump nozzle or other robust obstruction.
Unfortunately, merely by limiting the amount of force applied to the valve by the actuator is not a viable solution to the safety hazard associated with closure of the valve. Despite the need to provide safe conditions during closing, it also necessary to close the valve with sufficient force to work with system features such as seals and gaskets that provide resistance or that need to be compressed by the actuator during some portion of the operation. Also, environmental conditions such as temperature extremes, dust, dirt and ice should not cause the unit to become inoperable due to the actuator not generating sufficient closure force. It may also be desirable for the actuator to firmly hold the ball valve against positive stops. For these and other related reasons, it is not viable to provide for safe operation merely by using a low force actuator.
Accordingly, there is a need in the art for an actuator that provides an efficient and reliable anti-pinch protection that interrupts normal operation under certain load conditions. There is a further need in the art for an actuator that safely and reliably closes a valve mechanism for an automotive fuel filler port.
An electromechanical actuator consistent with the invention includes an electric motor and a conductive path normally connecting the motor for receiving a power supply input. An output gear is coupled to an output shaft of the motor, and an output shaft structure is coupled to the output gear to allow relative motion between the output shaft structure and the output gear upon application of a predetermined level of force to the output shaft structure. The relative motion between the output gear and the output shaft structure opens the conductive path. Integrated position control is provided by configuration of stationary contacts whereby the conductive path is opened at limits to the range of motion for the output shaft established by location of the ends of the stationary contacts.
A fuel filler valve system consistent with the invention includes a valve disposed between a vehicle fuel filler port and a vehicle fuel tank, and an actuator consistent with the invention for moving the valve between the open and closed positions. A method of providing pinch protection in a movable mechanism consistent with the invention includes coupling the mechanism to an actuator consistent with the invention, and energizing the actuator motor to drive the mechanism.